Emails from Clinton's private address included correspondence with top White House staffers. Photo: Reuters/Stephen Lam

Among the 3,000 pages of Hillary Clinton emails released Tuesday night by the State Department were entreaties from former President Jimmy Carter over North Korea, concerns regarding a “twittering” Hillary impostor, and a six-email chain discussing the mechanics of fax machines.

As reporters sift through the approximately 1,900 emails, questions have arisen surrounding who knew about Clinton's private email address. In one email, State Department aide Cheryl Mills asked Clinton if she wanted Rahm Emanuel, then President Obama’s chief of staff, to have her private email address. Clinton’s response: “Yes.”

In another, Mills told Clinton that White House strategist David Axelrod inquired after her email. Clinton responded that "I can't look at it all day," referring to her inbox, noting that he should be told to contact aides during work hours.

The release comes as Clinton, a 2016 Democratic presidential hopeful, continues to weather criticism over using personal email addresses while serving as secretary of state. Critics questioned how the arrangement affected government security and record keeping. According to the Associated Press, Clinton received at least 12 messages in 2009 that were later marked "confidential."

The cache, which covered March through December 2009, is the first installment released in response to a court order mandating the State Department to make public some 55,000 Clinton emails by Jan. 29, 2016. The State Department has previously released some 300 emails related to the terrorist attacks in Benghazi, Libya, which left four Americans dead, including U.S. Ambassador Christopher Stephens.

As she ramps up her presidential campaign, Clinton has encouraged the government to publish the entire trove of emails. But recent reports that Clinton failed to turn over 15 emails from around the time of the Benghazi fiasco have raised new questions over her email policy and her commitment to transparency.

Also making an appearance in the emails is Sidney Blumenthal, a confidante whose near-constant presence in Clinton’s inbox has raised eyebrows. In most cases, Blumenthal updated Clinton on global political affairs and forwarded articles that he thought might interest her.

On June 5, 2009, Mills forwarded Clinton a cryptic message from Philip Crowley, assistant secretary of state for public affairs, with the subject, “Sydney Blumenthal [sic].” The email read: “FYI, we have heard from an AP reporter that Sydney outed himself about coming to the Department, mentioning it without realizing he was talking to someone who actually covers our building.”

Clinton also received emails on her private address from Cherie Blair, wife of British Prime Minister Tony Blair, Senator Barbara Mikulski, and former Secretary of State Colin Powell, who wished her well after she broke her elbow.

As the Associated Press noted, it's not clear whether officials were aware that Clinton's email was being run from a server in her New York home.